Image sensors convert optical light to an electrical signal. Image sensors are formed from an array of pixels, each of which converts light received from a light source into an electrical signal. Conventional image sensors are used predominantly in digital cameras, and may fall into one of two categories: charge-coupled device (CCD) image sensors and complementary metal-oxide-semiconductor (CMOS) image sensors. Many applications for image sensors require a higher dynamic range (i.e. a higher differentiation of luminance) than may be achieved with conventional CMOS image sensors. Thus, improvements in the dynamic range of image sensors are desired.